While the data-gathering Juno will be performing requires an unusually low orbit, this necessity has presented several major technical challenges. The intense power of Jupiter’s magnetic field would ordinarily play havoc with sensitive scientific equipment, require special radiation shielding—Juno’s central computer is housed inside a dense titanium shell. Currently, all non-essential systems are shut down, as Juno prepares to make the critical rocket burn that will allow it to achieve orbit. Inside a gravity well as great as Jupiter’s, precision is everything: even the slightest misstep in the probe’s rocket burn could send it plunging to its doom.
Juno has already begun imaging Jupiter and its four major moons – Io, Europa, Ganymede and Callisto. Scott Bolton, Juno’s principle investigator, said these images are just a taste of what is to come: ‘‘In the future, we will see Jupiter’s polar auroras from a new perspective. We will see details in rolling bands of orange and white clouds like never before, and even the Great Red Spot’’. Jupiter’s huge auroras are of particular interest; they are among the largest and brightest in the solar system, due to Jupiter’s immense magnetic field. Juno’s polar orbit will allow it to study Jupiter’s magnetic field in more detail than ever before.
The probe’s name is a fitting reference to the classical mythology the planets are named after. Juno was Jupiter’s wife, who in one particular myth, parted the clouds Jupiter was hiding behind to spy on his secret deeds. And this is, in essence, the mission of the Juno probe—to peer through the dense clouds of Jupiter’s atmosphere in an attempt to perceive the very origins of the planet.
Two theories abound regarding the formation of Jupiter, one of which Juno will hopefully put to rest. Some argue that Jupiter was originally a dense rocky planet, which through its intense gravity, sucked in huge amounts of gas to become the enormous gas giant we know today. Another theory suggests that Jupiter formed in a very similar manner to our Sun: a dense pocket of gas that collapsed in on itself under its own gravity to become a spherical object, although Jupiter lacked the size and mass to ignite into a star like our Sun did. Juno will attempt to peer through the dense cloud layers to determine if Jupiter possesses a rocky core or not, which will provide a clearer understanding of how gas giants such as Jupiter came to be.
However, researchers will have to work quickly to gather their data. Despite the heavy shielding in the probe’s design, the intense radiation surrounding Jupiter will eventually spell its doom. ‘‘The constant bombardment will break the atomic bonds in Juno’s electronics”, said Heidi Becker, Juno’s Chief Radiation Monitoring Investigator. In this harsh environment, Juno is not expected to last much longer than its projected 20-month lifespan.
Nonetheless, the derelict probe will still hold surprises for future space explorers. The probe carries three aluminium Lego figures depicting the gods Jupiter and Juno, as well as the discoverer of Jupiter’s four major moons, Galileo Galilei.
– Greg Taylor, Correspondent (Science)